Summary of Work: G-proteins have many properties suggestive of multimeric proteins such as actin and tubulin. Moreover, immunocytochemical analysis using imaging techniques (concoval microscopy) reveal punctate structures of Gs, Gi, and Go associated with the cytoskeletal network (particularly actin but also tubulin). Caveolae, invaginations of the surface membrane, have been investigated by purification of the membranes and immunochemical probes of the components. In NIH 3T3 cells, caveolae appear to contain G-proteins, but the purity of the structures remains uncertain. New purification procedures are being investigated along with efforts to further identify the punctate structures associated with the cytoskeletal network. The latter studies are being investigated with monoclonal antibodies linked to gold particles.